The present invention relates generally to orthodontic brackets for providing orthodontic treatment of maloccluded teeth, and more specifically relates to a self-ligating orthodontic bracket with a sliding door for releasably retaining an archwire in a bracket slot.
Orthodontic brackets or braces are a very popular method of treating misaligned or maloccluded teeth. Traditionally, brackets are bonded to the labial or possibly lingual surfaces of a patient's teeth, and an archwire is placed in the slot of each bracket to guide movement of the teeth. Brackets are generally pre-adjusted to have built-in prescriptions of torque, tip, and in-out which are optimized for average cases of tooth movement. For instance, a bracket may be angled with respect to an occlusal plane (i.e. the bracket has a “tip angle”), depending on the tooth on which the bracket is to be placed. A ligature or ligating module, typically an elastomeric band such as a rubber band, is placed around the tie wings of a bracket to hold the archwire in place. However, ligatures typically cause friction on the wire during movement, resulting in a relatively slow treatment process, and they tend to attract plaque and trap food particles, a common cause of tooth decay or infection. As a result, the use of self-ligating orthodontic brackets has steadily become a prevalent alternative solution to malocclusion treatment.
A self-ligating orthodontic bracket does not require a ligature to hold the archwire in place. Rather, the bracket uses a clip or slide which opens and closes to releasably retain the archwire in the bracket slot. Thus, friction on wire movement is reduced compared to conventional brackets, resulting in potentially faster treatment time. An example of a conventional self-ligating bracket includes a base for attachment to a tooth surface, an archwire slot sized for receiving an archwire, a channel formed upon the base and transversely oriented to the archwire slot, and a sliding member slidably retained in the channel and closeable over the archwire slot. The sides of the bracket are crimped to securely retain the sliding member. Another type of self-ligating bracket includes a flexible pin to secure the sliding member in the closed position. However, these types of self-ligating brackets require additional processes or additives for securing the sliding member to the bracket, thus adding an additional layer of manufacturing complexity and increased cost.
Additionally, errors made while coining, bending, or crimping the sides of the bracket to retain the sliding member are typically irreversible without damaging the bracket, thus potentially resulting in significantly higher expenditures. For example, too much compression applied to the sides of the bracket may preclude the sliding member from moving, thus requiring the brackets to be discarded. Moreover, too little compression applied to the sides of the bracket may cause the sliding member to accidentally disengage from the bracket during use, resulting in patient and physician dissatisfaction and possible bracket recalls.
Hence, it is desirable to facilitate the assembly process by providing a self-ligating bracket that does not require crimping, bending, coining, fastening, or gluing the sliding member to the bracket. Additionally, it is desirable to provide a self-ligating bracket that is easy to manufacture and assemble, that is cost-effective, that requires no adhesives nor additives to assemble the sliding member to the bracket, and that reduces plaque buildup through minimal empty space in the bracket. It is further desirable to provide a self-ligating orthodontic bracket that can passively or actively express the bracket's prescription by providing for the sliding member to fully enclose the archwire in the bracket slot. Moreover, it is desirable to provide metallic and aesthetic self-ligating brackets with lower profiles, improved patient comfort, ease of manufacture, improved door operation, and improved visual orthodontic references. The present invention meets these and other needs.